1. Technical Field
The present invention relates to an electromagnetic relay having a main contact unit which is inserted into a power supply path to a load and an arc contact unit which is connected in parallel to the main contact unit.
2. Related Art
Conventionally, as shown in FIG. 8, there is known an electromagnetic relay in which a main contact unit 2 and an arc contact unit 3 which are connected in parallel to each other are built in a frame body 1′ and the main contact unit 2 and the arc contact unit 3 are inserted into a power supply path to a load (see JP-A-2000-164100).
The main contact unit 2 is made of a material having a small contact resistance and the arc contact unit 3 is made of a material having excellent adhesion resistibility. Therefore, by allowing the arc contact unit 3 to be closed after the main contact unit 2 is closed and allowing the arc contact unit 3 to be opened after the main contact unit 2 is opened, the opening and closing of the power supply path to the load can be performed mainly by the arc contact unit 3 having the adhesion resistibility and the power supply to the load can be performed mainly by the main contact unit 2 having small loss. That is, an electrical path for the main contact unit 2 requires a sectional area corresponding to a current capacity and thus in the relay disclosed in JP-A-2000-164100 (see paragraphs 0022 to 0023 and FIG. 15), the sectional area of the electrical path for the main contact unit 2 is secured by a main contact spring 23 and a braided wire 23′, by connecting the braided wire 23′ to the main contact spring 23 to which a main mobile contact 25 constituting the main contact unit 2 is attached.
As described above, since the electromagnetic relay having the configuration described in JP-A-2000-164100 requires the braided wire 23′, a technique of facilitating the welding of the braided wire 23′ has been suggested. In other words, since the braided wire 23′ is essential, there is a problem with increase in the number of process steps for welding the braided wire 23′. In addition, since the braided wire 23′ is required as an essential element of the main contact unit 2, there is a problem with increase in the number of elements.